Stimulating the vision system of a subject with vision impairments may improve their visual performance of patients. For example, as documented in U.S. Pat. No. 6,464,356, and US Published Patent Application No. 2005/0213033, which are hereby incorporated by reference herein in their entirety, presenting visual stimuli to the areas of a human's visual system may allow improvement in the user's vision. Such a procedure may be carried out on a personal computer for home use, the therapy performed in sessions on a daily schedule for a set period of time (e.g., an hour).
The location and orientation of a user's head relative to a display, used to present visual stimuli, needs to be identified each time therapy is performed to properly stimulate the correct zones in a user's visual field. Previous therapeutic regimens relied upon a user fixing their gaze in a particular location. The natural tendency of persons to move after being in an unsupported, fixed position for a relatively long period of time may cause misalignment of the visual stimuli relative to a user's visual field. Such misalignment may limit the effectiveness of a therapeutic session. Even if a user attempts to remain stationary relative to a display, identifying the proper position may be difficult, especially for individual users outside of a clinical setting. In addition, the amount of time required to properly align the relative position of the display with a user's visual field can be substantial.
Because devices for visual field testing and therapy tend to be bulky, they are typically used in dedicated facilities. However, it may be inconvenient to transport a patient to such a facility. It may therefore be desirable to use such a device in non-dedicated facilities such as a home, rehabilitation center, or hospital room. Additionally, positional adjustment of the subject relative to the source of stimulus may be overly time consuming or difficult.